/**
  ******************************************************************************
  * @file    ymodem.c 
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    29-May-2012
  * @brief   Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2012 STMicroelectronics</center></h2>
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
  */
/* Includes ------------------------------------------------------------------*/
#include "ymodem.h"
#include "uart_app.h"
#include "stm32f10x.h"
#include "flash_app.h"
#include <string.h>

/** @addtogroup STM32F1xx_IAP
  * @{
  */
  
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
extern uint8_t FileName[];

/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Receive byte from sender
  * @param  c: Character
  * @param  timeout: Timeout
  * @retval 0: Byte received
  *         -1: Timeout
  */
static  int32_t Receive_Byte (uint8_t *c, uint32_t timeout)
{
    while (timeout-- > 0)
    {
        if (SerialKeyPressed(c) == 1)
        {
            return 0;
        }
    }
    
    return -1;
}

/**
  * @brief  Send a byte
  * @param  c: Character
  * @retval 0: Byte sent
  */
static uint32_t Send_Byte (uint8_t c)
{
    Serial_PutChar(c);
    return 0;
}

/**
  * @brief  Update CRC16 for input byte
  * @param  CRC input value 
  * @param  input byte
  * @retval Updated CRC value
  */
uint16_t UpdateCRC16(uint16_t crcIn, uint8_t byte)
{
    uint32_t crc = crcIn;
    uint32_t in = byte|0x100;

    do
    {
        crc <<= 1;
        in <<= 1;

        if(in&0x100)
        {
            ++crc;
        }
    
        if(crc&0x10000)
        {
            crc ^= 0x1021;
        }
    } while(!(in&0x10000));

    return (crc&0xffffu);
}

/**
  * @brief  Cal CRC16 for YModem Packet
  * @param  data
  * @param  length
  * @retval CRC value
  */
uint16_t Cal_CRC16(const uint8_t* data, uint32_t size)
{
    uint32_t crc = 0;
    const uint8_t* dataEnd = data+size;
  
    while(data<dataEnd)
    {
        crc = UpdateCRC16(crc,*data++);
    }
    
    crc = UpdateCRC16(crc,0);
    crc = UpdateCRC16(crc,0);

    return (crc&0xffffu);
}

/**
  * @brief  Cal Check sum for YModem Packet
  * @param  data
  * @param  length
  * @retval None
  */
uint8_t CalChecksum(const uint8_t* data, uint32_t size)
{
    uint32_t sum = 0;
    const uint8_t* dataEnd = data+size;
 
    while(data < dataEnd)
    {
        sum += *data++;
    }

    return (sum&0xffu);
}

/**
  * @brief  Receive a packet from sender
  * @param  data
  * @param  length
  * @param  timeout
  *          0: end of transmission
  *          -1: abort by sender
  *          >0: packet length
  * @retval 0: normally return
  *         -1: timeout or packet error
  *         1: abort by user
  */
static int32_t Receive_Packet (uint8_t *data, int32_t *length, uint32_t timeout)
{
    uint16_t i, packet_size, computedcrc;
    uint8_t c;
    
    *length = 0;
    if (Receive_Byte(&c, timeout) != 0)
    {
        return -1;
    }
    
    switch (c)
    {
        case SOH:
            packet_size = PACKET_SIZE;
            break;
        case STX:
            packet_size = PACKET_1K_SIZE;
            break;
        case EOT:
            return 0;
        case CA:
            if ((Receive_Byte(&c, timeout) == 0) && (c == CA))
            {
                *length = -1;
                return 0;
            }
            else
            {
                return -1;
            }
        case ABORT1:
        case ABORT2:
            return 1;
        default:
            return -1;
    }
    
    *data = c;
    for (i = 1; i < (packet_size + PACKET_OVERHEAD); i ++)
    {
        if (Receive_Byte(data + i, timeout) != 0)
        {
            return -1;
        }
    }
    
    if (data[PACKET_SEQNO_INDEX] != ((data[PACKET_SEQNO_COMP_INDEX] ^ 0xff) & 0xff))
    {
        return -1;
    }
    
    /* Compute the CRC */
    computedcrc = Cal_CRC16(&data[PACKET_HEADER], (uint32_t)packet_size);
    /* Check that received CRC match the already computed CRC value
        data[packet_size+3]<<8) | data[packet_size+4] contains the received CRC 
        computedcrc contains the computed CRC value */
    if (computedcrc != (uint16_t)((data[packet_size+3]<<8) | data[packet_size+4]))
    {
        /* CRC error */
        return -1;
    }
    
    *length = packet_size;
    return 0;
}

/**
  * @brief  Receive a file using the ymodem protocol
  * @param  buf: Address of the first byte
  * @retval The size of the file
  */
int32_t Ymodem_Receive (uint8_t *buf)
{
    uint8_t packet_data[PACKET_1K_SIZE + PACKET_OVERHEAD], file_size[FILE_SIZE_LENGTH], *file_ptr, *buf_ptr;
    int32_t i, packet_length, session_done, file_done, packets_received, errors, session_begin, size = 0;
    uint32_t flashdestination, ramsource;

    /* Initialize flashdestination variable */
    flashdestination = APPLICATION_ADDRESS;
  
    for (session_done = 0, errors = 0, session_begin = 0; ;)
    {
        for (packets_received = 0, file_done = 0, buf_ptr = buf; ;)
        {
            switch (Receive_Packet(packet_data, &packet_length, NAK_TIMEOUT))
            {
                case 0:
                    errors = 0;
                    switch (packet_length)
                    {
                        /* Abort by sender */
                        case - 1:
                            Send_Byte(ACK);
                            return 0;
                        /* End of transmission */
                        case 0:
                            Send_Byte(ACK);
                            file_done = 1;
                            break;
                        /* Normal packet */
                        default:
                        if ((packet_data[PACKET_SEQNO_INDEX] & 0xff) != (packets_received & 0xff))
                        {
                            Send_Byte(NAK);
                        }
                        else
                        {
                            if (packets_received == 0)
                            {
                                /* Filename packet */
                                if (packet_data[PACKET_HEADER] != 0)
                                {
                                    /* Filename packet has valid data */
                                    for (i = 0, file_ptr = packet_data + PACKET_HEADER; (*file_ptr != 0) && (i < FILE_NAME_LENGTH);)
                                    {
                                        FileName[i++] = *file_ptr++;
                                    }
                                    FileName[i++] = '\0';
                                    
                                    for (i = 0, file_ptr ++; (*file_ptr != ' ') && (i < (FILE_SIZE_LENGTH - 1));)
                                    {
                                        file_size[i++] = *file_ptr++;
                                    }
                                    file_size[i++] = '\0';
                                    Str2Int(file_size, &size);
                
                                    /* Test the size of the image to be sent */
                                    /* Image size is greater than Flash size */
                                    if (size > (USER_FLASH_SIZE + 1))
                                    {
                                        /* End session */
                                        Send_Byte(CA);
                                        Send_Byte(CA);
                                        return -1;
                                    }
                                    /* erase user application area */
                                    FLASH_APP_Erase(APPLICATION_ADDRESS);
                                    Send_Byte(ACK);
                                    Send_Byte(CRC16);
                                }
                                /* Filename packet is empty, end session */
                                else
                                {
                                    Send_Byte(ACK);
                                    file_done = 1;
                                    session_done = 1;
                                    break;
                                }
                            }
                            /* Data packet */
                            else
                            {
                                memcpy(buf_ptr, packet_data + PACKET_HEADER, packet_length);
                                ramsource = (uint32_t)buf;
            
                                /* Write received data in Flash */
                                if (FLASH_APP_Write(flashdestination, (uint32_t*) ramsource, (uint16_t) packet_length/4)  == 0)
                                {
                                    Send_Byte(ACK);
                                    flashdestination += packet_length;
                                }
                                else /* An error occurred while writing to Flash memory */
                                {
                                    /* End session */
                                    Send_Byte(CA);
                                    Send_Byte(CA);
                                    return -2;
                                }
                            }
                            
                            packets_received ++;
                            session_begin = 1;
                        }
                    }
                    break;
                case 1:
                    Send_Byte(CA);
                    Send_Byte(CA);
                    return -3;
                default:
                    if (session_begin > 0)
                    {
                        errors ++;
                    }
                    if (errors > MAX_ERRORS)
                    {
                        Send_Byte(CA);
                        Send_Byte(CA);
                        return 0;
                    }
                    Send_Byte(CRC16);
                    break;
            }
            if (file_done != 0)
            {
                break;
            }
        }
        
        if (session_done != 0)
        {
            break;
        }
    }
    
    return (int32_t)size;
}

/**
  * @brief  check response using the ymodem protocol
  * @param  buf: Address of the first byte
  * @retval The size of the file
  */
uint32_t Ymodem_CheckResponse(uint8_t c)
{
  return 0;
}

/**
  * @brief  Prepare the first block
  * @param  timeout
  * @retval None
  */
void Ymodem_PrepareIntialPacket(uint8_t *data, const uint8_t* fileName, uint32_t *length)
{
  uint16_t i, j;
  uint8_t file_ptr[10];
  
  /* Make first three packet */
  data[0] = SOH;
  data[1] = 0x00;
  data[2] = 0xff;
  
  /* Filename packet has valid data */
  for (i = 0; (fileName[i] != '\0') && (i < FILE_NAME_LENGTH);i++)
  {
     data[i + PACKET_HEADER] = fileName[i];
  }

  data[i + PACKET_HEADER] = 0x00;
  
  Int2Str (file_ptr, *length);
  for (j =0, i = i + PACKET_HEADER + 1; file_ptr[j] != '\0' ; )
  {
     data[i++] = file_ptr[j++];
  }
  
  for (j = i; j < PACKET_SIZE + PACKET_HEADER; j++)
  {
    data[j] = 0;
  }
}

/**
  * @brief  Prepare the data packet
  * @param  timeout
  * @retval None
  */
void Ymodem_PreparePacket(uint8_t *SourceBuf, uint8_t *data, uint8_t pktNo, uint32_t sizeBlk)
{
  uint16_t i, size, packetSize;
  uint8_t* file_ptr;
  
  /* Make first three packet */
  packetSize = sizeBlk >= PACKET_1K_SIZE ? PACKET_1K_SIZE : PACKET_SIZE;
  size = sizeBlk < packetSize ? sizeBlk :packetSize;
  if (packetSize == PACKET_1K_SIZE)
  {
     data[0] = STX;
  }
  else
  {
     data[0] = SOH;
  }
  data[1] = pktNo;
  data[2] = (~pktNo);
  file_ptr = SourceBuf;
  
  /* Filename packet has valid data */
  for (i = PACKET_HEADER; i < size + PACKET_HEADER;i++)
  {
     data[i] = *file_ptr++;
  }
  if ( size  <= packetSize)
  {
    for (i = size + PACKET_HEADER; i < packetSize + PACKET_HEADER; i++)
    {
      data[i] = 0x1A; /* EOF (0x1A) or 0x00 */
    }
  }
}

/**
  * @brief  Transmit a data packet using the ymodem protocol
  * @param  data
  * @param  length
  * @retval None
  */
void Ymodem_SendPacket(uint8_t *data, uint16_t length)
{
  uint16_t i;
  i = 0;
  while (i < length)
  {
    Send_Byte(data[i]);
    i++;
  }
}

/**
  * @brief  Transmit a file using the ymodem protocol
  * @param  buf: Address of the first byte
  * @retval The size of the file
  */
uint8_t Ymodem_Transmit (uint8_t *buf, const uint8_t* sendFileName, uint32_t sizeFile)
{
  uint8_t packet_data[PACKET_1K_SIZE + PACKET_OVERHEAD];
  uint8_t FileName[FILE_NAME_LENGTH];
  uint8_t *buf_ptr, tempCheckSum ;
  uint16_t tempCRC, blkNumber;
  uint8_t receivedC[2], CRC16_F = 0, i;
  uint32_t errors = 0, ackReceived = 0, size = 0, pktSize;

  for (i = 0; i < (FILE_NAME_LENGTH - 1); i++)
  {
    FileName[i] = sendFileName[i];
  }
  CRC16_F = 1;
  
  /* Prepare first block */
  Ymodem_PrepareIntialPacket(&packet_data[0], FileName, &sizeFile);
  
  do 
  {
    /* Send Packet */
    Ymodem_SendPacket(packet_data, PACKET_SIZE + PACKET_HEADER);
    
    /* Send CRC or Check Sum based on CRC16_F */
    if (CRC16_F)
    {
       tempCRC = Cal_CRC16(&packet_data[3], PACKET_SIZE);
       Send_Byte(tempCRC >> 8);
       Send_Byte(tempCRC & 0xFF);
    }
    else
    {
       tempCheckSum = CalChecksum (&packet_data[3], PACKET_SIZE);
       Send_Byte(tempCheckSum);
    }
  
    /* Wait for Ack and 'C' */
    if (Receive_Byte(&receivedC[0], 1000000) == 0)  
    {
      if (receivedC[0] == ACK)
      { 
        /* Packet transfered correctly */
        ackReceived = 1;
      }
    }
    else
    {
        errors++;
    }
  }while (!ackReceived && (errors < 0x0A));
  
  if (errors >=  0x0A)
  {
    return errors;
  }
  buf_ptr = buf;
  size = sizeFile;
  blkNumber = 0x01;

  /* Here 1024 bytes package is used to send the packets */
  while (size)
  {
    /* Prepare next packet */
    Ymodem_PreparePacket(buf_ptr, &packet_data[0], blkNumber, size);
    ackReceived = 0;
    receivedC[0]= 0;
    errors = 0;
    do
    {
      /* Send next packet */
      if (size >= PACKET_1K_SIZE)
      {
        pktSize = PACKET_1K_SIZE;
       
      }
      else
      {
        pktSize = PACKET_SIZE;
      }
      Ymodem_SendPacket(packet_data, pktSize + PACKET_HEADER);
      /* Send CRC or Check Sum based on CRC16_F */
      if (CRC16_F)
      {
         tempCRC = Cal_CRC16(&packet_data[3], pktSize);
         Send_Byte(tempCRC >> 8);
         Send_Byte(tempCRC & 0xFF);
      }
      else
      {
        tempCheckSum = CalChecksum (&packet_data[3], pktSize);
        Send_Byte(tempCheckSum);
      }
      
      /* Wait for Ack */
      if (Receive_Byte(&receivedC[0], 1000000) == 0)  
      {    if (receivedC[0] == ACK)
      {
        ackReceived = 1;  
        if (size > pktSize)
        {
           buf_ptr += pktSize;  
           size -= pktSize;
           if (blkNumber == (USER_FLASH_SIZE/1024))
           {
             return 0xFF; /*  error */
           }
           else
           {
              blkNumber++;
           }
        }
        else
        {
           buf_ptr += pktSize;
           size = 0;
        }
      }
      }
      else
      {
        errors++;
      }
    }while(!ackReceived && (errors < 0x0A));
    
    /* Resend packet if NAK  for a count of 10 else end of commuincation */
    if (errors >=  0x0A)
    {
      return errors;
    }
    
  }
  ackReceived = 0;
  receivedC[0] = 0x00;
  receivedC[1] = 0x00;
  errors = 0;
  do 
  { 
    Send_Byte(EOT);   
    /* Send (EOT); */
    /* Wait for Ack */
    receivedC[0] = USART_ReceiveData(USART1_PORT);
    if (receivedC[0] == ACK)
    {
      ackReceived = 1;
      }
    
    else
    {
      errors++;
    }
    /* Clear Overrun flag of the USART2 */
    USART_ClearFlag(USART1_PORT, USART_FLAG_ORE);
  }while (!ackReceived && (errors < 0x0A));
    
  if (errors >=  0x0A)
  {
    return errors;
  }
  
  /* Last packet preparation */
  ackReceived = 0;
  receivedC[0] = 0x00;
  receivedC[1] = 0x00;
  errors = 0;

  packet_data[0] = SOH;
  packet_data[1] = 0;
  packet_data [2] = 0xFF;

  for (i = PACKET_HEADER; i < (PACKET_SIZE + PACKET_HEADER); i++)
  {
     packet_data [i] = 0x00;
  }
  
  do 
  {
    /* Send Packet */
    Ymodem_SendPacket(packet_data, PACKET_SIZE + PACKET_HEADER);

    /* Send CRC or Check Sum based on CRC16_F */
    tempCRC = Cal_CRC16(&packet_data[3], PACKET_SIZE);
    Send_Byte(tempCRC >> 8);
    Send_Byte(tempCRC & 0xFF);
  
    /* Wait for Ack and 'C' */
    if (Receive_Byte(&receivedC[1], 1000000) == 0)  
    {
      if (receivedC[1] == ACK)
      { 
        /* Packet transfered correctly */
        ackReceived = 1;
      }
    }
    else
    {
      errors++;
    }
  }while (!ackReceived && (errors < 0x0A));
  
  /* Resend packet if NAK  for a count of 10  else end of commuincation */
  if (errors >=  0x0A)
  {
    return errors;
  }  
  receivedC[0] = 0x00;
  do 
  { 
    Send_Byte(EOT);   
    /* Send (EOT); */
    /* Wait for Ack */
    if ((Receive_Byte(&receivedC[0], 1000000) == 0)  && receivedC[0] == ACK)
    {
      ackReceived = 1;  
    }
    
    else
    {
      errors++;
    }
    /* Clear Overrun flag of the USART2 */
    USART_ClearFlag(USART1_PORT, USART_FLAG_ORE);
  }while (!ackReceived && (errors < 0x0A));
    
  if (errors >=  0x0A)
  {
    return errors;
  }
  return 0; /* file trasmitted successfully */
}

/**
  * @}
  */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
